Deco time when NO GAS SWITCH

Legacy OSTC's
gorcio
Posts: 187
Joined: Sunday 2. May 2010, 22:20

Deco time when NO GAS SWITCH

Post by gorcio »

Hi,

just noticed as a result of investigating problem with another computer, that when diving with eg air with active O2 on the gas list, and NOT switching to the O2 - OSTC will keep displaying deco time as calculated for O2, but will time the deco stop slower comparing to the dive time clock above. So, in my case - 24m/30' dive, resulted in 9m/1' and 6m/3' with O2 active. But NOT switching to O2, display remained at 3 minutes, while clock counted around 9 minutes.
I am not sure if that's intended behaviour or not, but could you by any chance force showing normal deco time in case of NO SWITCH ?
Kind regards,
Gorcio, OSTC MK2 828
heinrichsweikamp
Posts: 4370
Joined: Sunday 13. May 2007, 18:07

Re: Deco time when NO GAS SWITCH

Post by heinrichsweikamp »

Hi,

If you stay up 1.5m above the planned gas change the OSTC continues to assume you'll do the change. If you're not changing, the time will decrease slower then shown.
If you ascent more then 1.5m above the change depth the OSTC will recompute the decompression plan.

Regards,
Matthias
tiefunten
Posts: 284
Joined: Wednesday 18. May 2011, 23:58

Re: Deco time when NO GAS SWITCH

Post by tiefunten »

Wouldn't it make sense to switch from a change depth to a certain timeframe within a depth window instead?
kaheksa
Posts: 78
Joined: Thursday 12. April 2012, 17:30

Re: Deco time when NO GAS SWITCH

Post by kaheksa »

I always switch off the gasses im not using for that same exact reason. So I can always get the correct reading and you can switch to a gas even when it's not active so no problems
OSTC 2C - 7135
gorcio
Posts: 187
Joined: Sunday 2. May 2010, 22:20

Re: Deco time when NO GAS SWITCH

Post by gorcio »

Yeah, but the point (mine, matter of personal preference) is to dive with active gases and have a real-time picture of deco schedule based on currently used gas. The deco schedule could be recomputed on the gas switch event. I believe OSTC has more than sufficient computing power for it.

Matthias, would it be possible to have such routine implemented based on one config parameter like Show Real Deco Schedule ? If 1 -> show deco times based on currently active gas. If 0 ->act as now, assuming gas switches WILL certainly happen and show deco runtime accordingly to properly and timely executed switches ?

Best regards
Gorcio
Kind regards,
Gorcio, OSTC MK2 828
heinrichsweikamp
Posts: 4370
Joined: Sunday 13. May 2007, 18:07

Re: Deco time when NO GAS SWITCH

Post by heinrichsweikamp »

Just configure your deco gases to 0m change depth. The schedule will be recomputed upon the gas change.

Regards,
Matthias
gorcio
Posts: 187
Joined: Sunday 2. May 2010, 22:20

Re: Deco time when NO GAS SWITCH

Post by gorcio »

This is a nice workaround, but again does not reflect real life and real time situation.

So ... could it be done please ?
Kind regards,
Gorcio, OSTC MK2 828
heinrichsweikamp
Posts: 4370
Joined: Sunday 13. May 2007, 18:07

Re: Deco time when NO GAS SWITCH

Post by heinrichsweikamp »

You want two decoplans simultaneously? One including gas changes and one based on the currently used gas?

Regards,
Matthias
gorcio
Posts: 187
Joined: Sunday 2. May 2010, 22:20

Re: Deco time when NO GAS SWITCH

Post by gorcio »

No, absolutely not. Unless it is possible and easy. But I rather meant a Custom Fucntion, that would allow user to choose how deco should be displayed - as a real-time info based on actual gas (the one being used), and recalculated after gas switch, OR the current deco schedule based on all active gases anticipating that gas switches will take place at configured depths.
Kind regards,
Gorcio, OSTC MK2 828
heinrichsweikamp
Posts: 4370
Joined: Sunday 13. May 2007, 18:07

Re: Deco time when NO GAS SWITCH

Post by heinrichsweikamp »

Just disable the deco gases (You can do this underwater, too) and you have this effect.

regards,
Matthias
gorcio
Posts: 187
Joined: Sunday 2. May 2010, 22:20

Re: Deco time when NO GAS SWITCH

Post by gorcio »

Thanks, but again - that would not be a real time situation. There are possible situations when you enter the water with deco gases and you do not switch to them.
I am sure that you are right and that it would work, but I do not like workarounds.
If such Custom Function could be implemented - it would be great and it would get OSTC in line with some other machines as well. If not ... I will live with it however I'd rather have it configurable as I described.
Kind regards,
Gorcio, OSTC MK2 828
heinrichsweikamp
Posts: 4370
Joined: Sunday 13. May 2007, 18:07

Re: Deco time when NO GAS SWITCH

Post by heinrichsweikamp »

gorcio Wrote:
> Thanks, but again - that would not be a real time
> situation. There are possible situations when you
> enter the water with deco gases and you do not
> switch to them.

That exactly what we have the enable/disable menu for.

Divemode Menu -> Gaslist -> More -> More and you can disable the deco gas underwater. It will no longer be used for deco calculations.

Regards,
Matthias
gorcio
Posts: 187
Joined: Sunday 2. May 2010, 22:20

Re: Deco time when NO GAS SWITCH

Post by gorcio »

Hopefully it will force deco recalculation ?
Still - one Custom Fucntion would act as global on/off switch for all active gasses apart from First Gas, which was my point. But I understand now your point too.
Kind regards,
Gorcio, OSTC MK2 828
heinrichsweikamp
Posts: 4370
Joined: Sunday 13. May 2007, 18:07

Re: Deco time when NO GAS SWITCH

Post by heinrichsweikamp »

Yes, this will recalculate the deco right away. A custom function would not be accessible underwater.

Regards,
Matthias
gorcio
Posts: 187
Joined: Sunday 2. May 2010, 22:20

Re: Deco time when NO GAS SWITCH

Post by gorcio »

The Custom Function would be just set on the surface. And that's it.
Kind regards,
Gorcio, OSTC MK2 828
scubatinoo
Posts: 666
Joined: Sunday 1. January 2012, 22:41

Re: Deco time when NO GAS SWITCH

Post by scubatinoo »

gorcio Wrote:
-------------------------------------------------------
> The Custom Function would be just set on the
> surface. And that's it.

Sorry, but if you can set any custom functions on surface, then
you should be able to set a proper gas list according to your dive
plan... so there's no need for your request.
regards,
scubatinoo

> OSTC 2N 3705 & OSTC 2 18807 <
gorcio
Posts: 187
Joined: Sunday 2. May 2010, 22:20

Re: Deco time when NO GAS SWITCH

Post by gorcio »

@scubatinoo - thank you but I don't think that :
1. you understood
2. you are authority on my request

In fact - you obviously have not understood so further discussion is pointless.

EOT.
Kind regards,
Gorcio, OSTC MK2 828
jb2cool
Posts: 142
Joined: Tuesday 21. January 2014, 21:19

Re: Deco time when NO GAS SWITCH

Post by jb2cool »

From what i can see there are sertain scenarios (All these are assuming one deco gas, i have no idea how it'll work with more than one);

A, Backgas and deco gas active with switch depth set correctly.
B, Backgas and deco gas active with switch depth set to 0m.
C, Backgas active but deco gas inactive.

Now as i understand it (Can someone confirm) the results of this are;

A, Deco shown is assuming switch to deco gas, deco on backgas will take longer. Deco shown will be recalculated to show the longer 'backgas only deco' once 1.5m shallower than change depth.
B, Deco shown is assuming deco will be on backgas, if deco gas is switched to then deco will be recalculated immediately.
C, Deco shown is assuming deco will be on backgas. The only way to change this would be to activate other gasses.

Gorcio,
From what i can see you want to use scenario B. This is my current preferance as i like to be able to plan to complete all deco on backgas (To account for lost deco gas) but if switching to a richer deco gas my deco will be reduced.
gorcio
Posts: 187
Joined: Sunday 2. May 2010, 22:20

Re: Deco time when NO GAS SWITCH

Post by gorcio »

jb2cool Wrote:
-------------------------------------------------------

> A, Backgas and deco gas active with switch depth
> set correctly.
> B, Backgas and deco gas active with switch depth
> set to 0m.
> C, Backgas active but deco gas inactive.
>
> Now as i understand it (Can someone confirm) the
> results of this are;

> B, Deco shown is assuming deco will be on backgas,
> if deco gas is switched to then deco will be
> recalculated immediately.

> Gorcio,
> From what i can see you want to use scenario B.
> This is my current preferance as i like to be able
> to plan to complete all deco on backgas (To
> account for lost deco gas) but if switching to a
> richer deco gas my deco will be reduced.

Actually, I would like to configure gases as in scenario A but what I would like to achieve is indeed result B (if by backgas we take currently active gas, which is not necessarily the same). I would like to be able to see deco as it is calculated on current gas, with NO assumptions as to gas switches. Active gases should stay active with proper change depth so that the unit could blink or do whatever it does at this depth. And if I switch - I would like to see deco recalculated as quickly as possible taking new gas into account. And if I have two active deco gases - still deco recalculated only for this new gas. When I switch again (say to O2) - then I would like it to be recalculated again.

Why would I like to do it ? Because it franky doesn't matter at all when you dive solo/runtime. But when you dive with a partner and you tell him 2 minutes, then in 2 minutes it will be gone, while now, in 2 minutes you will tell him .... yyyyyy, 1 minute ? 2 minutes ? Quiet assumption of course is - you keep your depth and do not run oscillator :-) And because I am a nice person and I don't want to force anything on others, I though that maybe Custom Function could be set to satisfy my need to have real data based on current situation with no assumption, while others could simply ignore this Custom Function which would then cause no change to currently implemented deco estimation.
Again - my 3 cents and just an idea.
Kind regards,
Gorcio, OSTC MK2 828
sailor
Posts: 401
Joined: Friday 11. April 2008, 23:16

Re: Deco time when NO GAS SWITCH

Post by sailor »

As mentioned bevor, just disable the deco gas and you are done.
You can still use a deco gas and TTS / deco will be calculated accordingly.
No need for another CF.
Titus
Posts: 23
Joined: Thursday 19. June 2014, 10:36

Re: Deco time when NO GAS SWITCH

Post by Titus »

just a quesion about Deco time calculation :

Matthias said that if we stay 1,5 m shallower than change depth, the deco plan will be automatically recalculated to use the current used gas as deco gas.
To be clear, let put an example.
I use 2 gas : Air and O2 100%, all active, all with their correct change depth (Air = 0 as first gas, O2 = 6m). I get a deco stop at 6m/2' and 3m/4' when I do the simulation (so taking my both gas into account).
When I ascent (so using air), I saw that my deco tank has issue (I can't use it).
I have 2 options :
- I switch off the O2 in the gaslist and my deco plan will be automatically recalculated by the computer
- I do nothing and I will see that my 2' at 6m will not be 2' but more.

So question, how this 1.5m shallower stuff can play a role ?

thanks for your answer.

Titus
Titus
jb2cool
Posts: 142
Joined: Tuesday 21. January 2014, 21:19

Re: Deco time when NO GAS SWITCH

Post by jb2cool »

Rich mixes like 80% and pure O2 have the unfortunate feature that their MOD is pretty much at the level of the typical stops required and if you go 1.5m shallower you are probably violating the deco ceiling. If using something like 50% for deco (MOD of 21m) then you'd have to rack up a lot of deco to have stops down to that depth so the 1.5m rule could be usefull there.

I guess you either have to wait it out and not know how much deco is left or turn the O2 off in the gas list to force recalculation.
Titus
Posts: 23
Joined: Thursday 19. June 2014, 10:36

Re: Deco time when NO GAS SWITCH

Post by Titus »

@jb2cool

Thanks but then let's take my example by using a 50% Nx but keeping same deco plan (6m/2'; 3m/4'). the deco plan has been done by using my both gas (Air + Nx50)

Does that mean that when I will reach about 19.5m, my initial decoplan that was 6' (2+4) will be adapted around 19,5m (MOD Nx50-1.5 = 21-1.5) and indicating me a higher decoplan than 6' because I have stayed on Air instead of swithing to Nx50 ?

Thanks,
Titus
jb2cool
Posts: 142
Joined: Tuesday 21. January 2014, 21:19

Re: Deco time when NO GAS SWITCH

Post by jb2cool »

Yes, that's my understanding of the way it works.

@ 19.5m your 6' of EAN50 deco will magically turn into 10' or so (Just guessing on number) on air deco.
Titus
Posts: 23
Joined: Thursday 19. June 2014, 10:36

Re: Deco time when NO GAS SWITCH

Post by Titus »

@jb2cool, Thanks

Can Matthias (@heinrichsweikamp) maybe confirm our understanding ?

Thanks
Titus
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